Micronutrient imbalance of sapota orchard in table lands of semi arid region of Rajasthan, India

Abstract

Micronutrient status of sapota crop was assessed by analyzing soil and plant samples from table lands of south eastern Rajasthan. Surface and sub surface soil samples were extracted with diethylene triamine penta acetic acid (DTPA), and plant samples (including leaf and petiole) digested with di-acid mixture for the estimation of available iron (Fe), manganese (Mn), copper (Cu) and zinc (Zn). The DTPA extractable micronutrients in the soil samples followed the order as Mn> Fe> Zn> Cu. The mean values of surface extractable DTPA Mn, Fe, Zn and Cu varied from 15.2 to 8.4, 8 to 3.4, 0.74 to 0.17 and 0.35 to 0.02 mg kg-1 respectively. Total Fe, Mn, Zn and Cu of leaf samples varied from 89.41 to 231.24, 22.2 to 97.61, 0.62 to 48.12 and 4.35 to 19.78 mg kg-1, respectively. Total Fe, Mn, Zn and Cu in petioles varied from 33.52 to 284.51, 11.31 to 69.26, 0.54 to 36 and 2.0 to 18.48 mg kg-1, respectively. Unlike soil micronutrient status, leaf sample analysis showed high Mn and Cu concentration, which resulted in Zn and Fe deficiency, resulting in shortened internodes or rosette disorders in sapota trees.